User input devices that include mechanical keys typically suffer from errors generated by key debounces. Key debounces are typically caused by mechanical bounces of the keys that generate glitches in the key signals. This, in turn, may lead to an incorrect detection of the key. For example, a key that is only pressed once may generate key debounce that may lead a keyboard controller to believe that the same key was pressed twice. Alternatively, the key debounce may cause the keyboard controller to believe that the key was not pressed at all.
A key debounce correction circuit inhibits an unintended double entry (or lack of entry) of a pressed key in a keyboard that may occur if the pressed key bounces when activated. However, typical key debounce systems are implemented in firmware and are dependent on the instruction cycles of a processor. These systems are relatively slow and may take up some of the processor execution time. Additionally, since the conventional systems are dependent on instruction cycles of the processor, their timing may not be uniform and predictable.
Therefore, there is a need for a hardware-based high performance key debounce correction method and circuit.